LAUSR

Abstract Besides being an essential macronutrient for plant growth, potassium (K) also acts as a stress-relieving agent against various biotic and abiotic stresses, especially water stress. An experiment consisting of three lowland Thai rice varieties (Pathumthani 1, RD57, RD41), two cultivation methods [dry direct seeding (DDS), transplanting (TP)] and four K doses (0, 80, 120,160 kg ha−1) under alternate wetting and drying (AWD) water regime was conducted to investigate the impact of K and cultivation method on lowland rice varieties subjected to AWD. Pathumthani 1 had significantly higher grain yield at the 120 kg K ha−1 compared with all other K doses. RD57 and RD41 had maximum grain yield at the 80 and 120 kg K ha−1, respectively, which was significantly higher than the control; however, grain yield among different K doses was mostly similar for RD57 and RD41. K application at the rate of 120 kg ha−1 for Pathumthani 1 and 80 kg ha−1 for RD57 and RD41 could be a feasible option. The performance of DDS and TP was better at the 80 and 120 kg K ha−1, respectively. Application of K at the optimum dose with proper selection of variety and cultivation method could help in sustainable rice production.